D-503 wrote:@Tyndmyr I acknowledge that additional research does reduce the chance of an unanticipated effect. I think the probabilities of an unexpected disastrous side effect from global warming and SRM are about on par because global warming has more expected effects than SO2 SRM leading to more ways for unexpended things to happen.

Well, we're pretty much all on board that "just keep on with global warming" is a bad plan, and should be curtailed regardless.

Risks that are about the same as something we acknowledge as a huge mistake....that's a point against it, not for it.

About 1 billion acres at around 3000 dollar/acre, plus a premium if you want to buy from people who weren't planning to sell, plus extra acres in between that are not currently part of a farm -> let's say 5 trillion to buy the land.

Then there's 2million farms. Another trillion to compensate for the loss of buildings and businesses? Lots of other people who work in agriculture and will need to relocate to new houses, and people who don't work in agriculture but whose income depended crucially on the farming community around them. Let's say 5 million households who need a new house at 200k per house, for yet another trillion? And you' ll need to build new infrastructure for the relocated people, and capital outlay for the new jobs.

Let's say, in total 10 trillion dollars (order of magnitude) if you want to do it eminent-domain style with ample compensations for at least the financial losses. Could be lot cheaper (to the public purse) if you go the full Soviet and just put the people on the train to some New City in the boonies.

After that initial outlay, you'll need to import food at higher prices, partially due to transportation costs, partially because US agriculture is cheaper than most alternatives, and partially because the loss of the entire US food production will raise world food prices.

US farm production is valued at half a trillion a year. Will take more to replace. Of course, this will be partially offset by the new jobs of the relocated people, and partially it is already taken into account in the capital losses estimated above(since the value of the lost land is based on future production). Still, it seems safe to budget at least several hundreds of billions/year, indefinitely, for the permanent efficiency loss going from domestic production to imports.

Granger Morgan quotes some sources that quantify the relative cost of cutting 80% of CO2 emissions (up to 5.5% of global GDP/year) versus equivalent albedo modification (somewhere in the range of 0.0002 to 0.2% of global GDP/year). You can see how that would be tempting to leaders facing an either/or decision.

The presentation also includes some horrifying plots of what happens if you pursue albedo modification for a few decades and then stop abruptly. You get a warming rate that can briefly spike to 4 K per decade. Then the rate goes down a bit, but you accumulate a lot of warming very quickly. If the ecological damage is a function of the rate of change even more than the absolute temperature offset, you had better be dead committed to an albedo modification program.

Planning frequently does not account for this possibility, but it's reasonably unlikely for ANY plan to survive to be implemented in technically optimal ways. Nuclear power was initially promised to be too cheap to meter on a similar basis. That proved to be...optimistic.